Antibodies are widely used in diagnostic assays in both human and veterinary medicine. Uses include enzyme-linked immunosorbent analysis (ELISA), quantitative antigen capture analysis, radioisotope-tagged reagents for in vivo localization of target antigens, and for in vivo localization of cytotoxic agents to target cells (i.e., immunotoxic therapy). The minimum epitope size for protein antigens is generally considered to be 5-6 amino acids, either as a linear sequence or as non-contiguous amino acids whose spatial placement defines the epitope (i.e., conformational epitope). Specificity is provided by the large number of potential amino acid epitopic sequences possible for a minimum epitope (i.e., 520).
Most commonly, large antigens or microbial organisms are used to induce antibody responses in order to insure the presentation of good antigenic sequences in the host animal. The use of these multivalent antigens for the production of polyclonal antibodies generally requires host-based adsorption of the sera to reduce non-specific cross-reactive antibody species. Monoclonal antibodies avoid this pitfall but frequently result in reagents whose specific epitopic specificity is unknown.
The invention relates to a method of identifying an antigenic amino acid subsequence from within a larger amino acid sequence comprising the steps of evaluating the hydrophilicity of subsequences of an amino acid sequence of interest; evaluating the flexibilitiy of subsequences of the amino acid sequence of interest; and selecting an amino acid subsequence having overlapping regions of hydrophilicity and flexibility. In particular embodiments, the larger amino acid sequence is selected from the group consisting of polypeptides expressed by members of the Chlamydia genus.
The invention also relates to antigenic amino acid subsequences identified by the methods described herein. In particular embodiments, the invention pertains to an antigenic amino acid subsequence selected from the group consisting of SEQ ID NOS: 1-118.
The invention also pertains to antibodies which are specific for the antigenic amino acid subsequences described herein. For example, the invention pertains to monoclonal antibodies specific for antigenic amino acid subsequences described herein.
The invention also relates to diagnostic and therapeutic methods utilizing the described antigenic amino acid subsequences and antibodies thereto.